Elimination of waste pits and use of the crude oil deposited in them involve highly technological activities. Any environmental restoration work carried out must be done within the corresponding legal context, which contains specific technical criteria that must be applied in order to evaluate and classify environmental impacts and ramifications, and to select the revitalization methods for restoring the soil and related vegetation properly. These standards usually contain the final specifications to be applied to environmental waste, including the respective measurement and inspection procedures. Environmental evaluations and audits that are conducted by any organization, governmental as well as private, must also be based on these technical elements and the respective legal ordinances.
Along these lines, the environmental restoration processes applied by the oil industry to oil-bearing waste pits are similar in every oilfield in the world, and refer to how each component of this liquid and solid oil-bearing waste found in these pits is treated. As concerns recovery of crude oil, technical specifications established by most oil companies, as an objective for its processing, address a maximum water and sediment content of one percent (1%). In light of the emulsifying nature of the oxidized and aged oil contained in these pits, above all those with heavy or extra-heavy crude, there can be no possibility of mixing it with freshly produced crude for dewatering. For the same reason, any measurement of the water content in the mixture, based on established standards, is inaccurate, which has led to contamination of crude batches in sales specifications, upon diluting the waste as a disposal method.
In order to recover this oil, conventional thermochemical processes applicable to heavy crude can also be used. Results of pilot testing carried out at various fields have in part been satisfactory. The cost of these methods has ranged from $5 to $25/bbl (US dollars per barrel of recovered oil), with no guarantee of crude recovery in sales specifications.
With regard to soil, the major oil companies have carried out pilot projects in the field applying biorecovery as a means of clean-up. The actual cost of this process has ranged from $30 to $60/m3 (US dollars per cubic meter of material removed). The market cost of other commercial technologies, such as thermal desorption, incineration and stabilization, is considerably higher, from $100 to $500/m3. Nevertheless, there are certain environmental limitations in instances where gas emissions are generated, or when any solution to the problem is simply put off.
The practice of filling is also foreseen in environmental regulations; however, confinement specifications result in higher costs in comparison to other alternatives.
In fact, both solid processing as well as use of the crude oil contained in waste pits are activities with a high technology content that call for major investments; however, the procedure commonly applied by most oilfield operators for environmental recovery involves only the usual blinding of existing pits.
Blinding consists of removing oil-bearing liquid and solid waste so as to free the pit itself of contamination caused by the hydrocarbons poured into it. At the same time, this waste is individually treated as follows: Liquids—water and oil, and usually emulsified—are taken to the nearest pumping station (by conveyor or pumping) to be treated, dewatered and made available in reinjection wells and/or for pumping to oil pipelines, respectively. Oil-bearing solids are sent to Handling Centers built for this purpose, where in general they become environment waste per se if they are not eventually disposed of in accordance with current environmental regulations by a scheduled time. Treatment and disposal of these materials once again requires operating outlays, making this an extremely expensive and repetitive process.
The Devices proposed in this Descriptive Report do not require compliance with such strict specifications as referred to above, with their high associated costs and low yield as observed. The equipment described in our process—once the oil-bearing residue contained in waste pits has been assessed and evaluated, and once the oil-bearing materials suitable for creating asphalt mixtures have been selected—then places them in the Crude Stabilization Tank to be subsequently processed by the Crude Treatment Device so that they can be upgraded and used in their entirety, at the same time complying with current environmental and road-building standards.
Work has also been carried out at the international level intended to improve the environment, such as techniques for manufacturing asphalt cement for use in building roadways. The following patents are particularly significant: ZEITZ HYDRIERWERK GMPH (Germany), no. DE4034321, published on May 23, 1991, wherein the inventors Erwin Kalhert et al. propose the preparation of asphalt for road paving using a mixture of bitumen and polybutadiene, gravel, sand, filling and sulfur; SMAC ACIEROID (France), no. EP0690102, published on Jan. 3, 1996, wherein the inventors Jeannot Beritzki et al. propose asphalt products with thermofusible organic binders; DEUTAG MISCHWERKE GMBH (Germany), no.
DE3729507, published on Mar. 23, 1989, wherein Kurt Ditter et al. create an environmentally-friendly process for recycling broken asphalt; MOBIL CORP (United States) U.S. Pat. No. 4,177,079, published on Dec. 4, 1979, wherein Wilton Espenschied invents a composition for asphalt pavement and a preparation method using organic solid waste; Dorozh Izyskatel, no. GB2047716, published on Dec. 3, 1980, for a proposal involving bitumen composition; Jie Yin, no. CN1080300, published on Jan. 5, 1994, for creating emulsified bentonite PRL and a method for its manufacturing; REPSOL PETROLEO SA (Spain), No. ES2069470, published on May 1, 1995, wherein the inventors Antonio Paez and Jesus Sanchez patent bitumen with a low asphaltene content, the uses and applications thereof; and NI SKIJ I POLIMERNYKH, ERIALOV, PERM Z IM S M KIROVA, No. RU2130040, published on May 10, 1999, whose inventors A. Mikov et al. create a binder for asphalt concrete mixtures.
More recently, the following works have been published during the past decade: a patent awarded to SMAC ACIEROID (France), No. FR2789419, published on Aug. 11, 2003, whereby the inventor, Jean Pierre Dean created roof lining seals with heat insulation, including granules embedded in the surface of asphalt seals that contain melted wax and elastomers; a patent awarded to TOHO CHEM IND LTD (Japan), No. EP1063263, published on Dec. 27, 2000 whose inventors (Seitaro Ando et al.) created a method for preparing paving materials using hot asphalt; a patent awarded to ROSTOVSKIJ G STR NYJ UNIVERSIT, No RU2149848, published on May 27, 2000, wherein the inventors (Bezrodnyj, O. K. et al.) invented an asphalt concrete mixture; a patent awarded to ROSTOVSKIJ G STR NYJ UNIVERSIT, No. RU2148063, published on Apr. 27, 2000, wherein Bezrodnyj, O. K. et al. created binding agents for road building; a patent awarded to INST NEFTEKHIMPERERABOTKI AKAD, RESPUB BASHKORTOSTAN K, No. RU2175037, published on Oct. 20, 2001, wherein Khisamutdinov. U. N. et al. invented an oil-polymer material for heat insulation; a patent awarded to NAJA AKADEMIJA, SAMARSKAJA G ARKHITEKTURNO STR, No. RU2174498, published on October 10, 200 [sic], wherein Nekljudov, A. G. et al. created a preparation of cold asphalt concrete with sand; a patent awarded to MATHY CONSTRUCTION COMPANY (United States), U.S. Pat. No. 6,399,680, published on Jun. 4, 2002, wherein Engber Steven and Reinke G. created a composition and preparation of modified polymer asphalt with an acid reaction; a patent awarded to FINA TECHNOLOGY, U.S. Pat. No. 6,407,152, published on Jun. 18, 2002, wherein Kelly, K. and Butler, J. created a method for preparing asphalt and polymer compounds, incorporating binding agents; a patent awarded to POLYPHALT LLC (Canada), U.S. Pat. No. 6,429,241, published on Aug. 6, 2002, wherein Liang Zhi-Zhong created bituminous compounds modified with elastomers; a patent awarded to TEXAS ENCORE MATERIALS INC (United States), U.S. Pat. No. 6,346,561, published on Feb. 12, 2002, wherein John D. Osborn (United States) proposes a type of material for pavements; and lastly, a patent awarded to UNIV LAVAL CITE UNIVERSITAIRE (Canada), U.S. Pat. No. 6,359,033, published on Mar. 19, 2002, where Abdellatif Ait-Kadi and Ali Akbar Yousefi presented their work on the composition of stable pavement with improvements for high and low temperatures. Nevertheless, all these patents differ substantially from our proposed invention.
In short, as can be seen, the aforementioned research and development work does not, fully or in part, take into consideration the overall use of oil-bearing residues obtained from the environmental cleaning of waste pits so as to convert them into material suitable for preparing asphalt mixtures to be used in the construction and paving of roads and other installations, as is clearly set forth in our process that includes Devices for Crude Oil Treatment and Upgrading, and which also provides an adequate solution for elimination of environmental waste existing in oilfields around the world.